dating
James Rubenstone
jimr at ldeo.columbia.edu
Fri Jul 13 09:40:36 EDT 2001
julia_webb27 at hotmail.com wrote:
>Could anyone give me any ideas for age dating corals other than by
>radiocarbon (C14) dating.
U-series disequilibrium dating, using 234U-230Th and (less
extensively) 235U-231Pa, gives excellent results for corals up to
several hundred thousands years old. Measuring the isotopes by mass
spectometry can give very precise ages (0.5% or better). One
advantage over radiocarbon is that U-series gives an absolute
(calendar) age, without the uncertainties inherent in radiocarbon
(reservoir corrections, variable production rate, variable surface
ocean inventory). The main problem is possible open-system behavior
of U and Th in fossil corals, particularly those that have seen
subaerial exposure. There are many examples of high quality coral
dates in the literature, from labs at Caltech, Minnesota, ANU,
Marseilles and Lamont-Doherty (and several others as well).
Jim Rubenstone
--
Dr. James Rubenstone email: jimr at ldeo.columbia.edu
Lamont-Doherty Earth Observatory voice: 845-365-8579
Columbia University fax: 845-365-8154
Palisades, NY 10964
~~~~~~~
For directions on subscribing and unsubscribing to coral-list or the
digests, please visit www.coral.noaa.gov, click on Popular on the
menu bar, then click on Coral-List Listserver.
More information about the Coral-list-old
mailing list